Anatomy- The Muscles .docx

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Western University
Anatomy and Cell Biology
Anatomy and Cell Biology 2221

Anatomy- The Muscles Muscles of the face  Frontalis o Two bellied muscle o 2 functions:  Occipital belly raises the eyebrows  Frontalis belly furrows the eyebrows  Orbicularis Oculi o Surrounds the eye, used for blinking  Zygomaticus major/minor o Smiling muscle o Stems of the zygomatic process o Insertion: the corner of the lips  Obicularis oris o Kissing muscle-sphincter around the mouth  Risorius o Cheeks toward the teeth whistle o Corner o the mouth, originates off parotid gland  Depressor anguli oris o Inserts at the corner of the mouth o Originates from the mandible  Platysma o Originates at the mandible o Inserts pectoralis major  Buccinator o Originates below and above the teeth o Inserts the corner of the mouth o Allows side to side movement of the mouth o Grouped in with the facial muscles because has the same innervation, but is also used in mastication  Innervation of the facial muscles is cranial nerve 7 Muscles of Mastication  Masseter o Originates from the zygomatic process down to the angle of the mandible o Bridge over the top of the temporalis muscle o Largest and strongest within the jaw o Innervated by the mandibular nerve  Temporalis o Originates on the temporal bone, deep under zygomatic arch o Inserts on the coronoid process of mandible o Helps in elevation of the jaw o Innervated by the mandibular nerve  Lateral Pteryoid o Inserts on the temporal mandibular joint o Originates on the Pteryoid o Assists in protraction and retraction of the jaw  Medial Pteryoid o Inserts of the inner mandibular angle originates on the Pteryoid process o Is the agonist Muscles of the tongue  Styloglossus o Originates from the styloid process and inserts on the under side of the tongue o Contraction: draw the tongue up and back  Hyoglossus o Originates on the hyoid bone o Inserts on the tongue o Downward movement of the tongue  Genioglossus o Antagonist to the Styloglossus o Originates from the inner side of the mandible to the tongue o Forward movement of the tongue  All of the above muscles are innervated by cranial never 12  Palatolglossus o Regurgitation o Originates from the tongue and inserts on the soft palate o Contraction: pulls down the soft plate o Innervated by the vagus never o Gag reflex Muscles of the eye  Medial rectus: adduction of the eye  Lateral rectus: abduction of the eye, innervated by the abducens Nerve CN VI  Superior rectus: elevate the eye  Inferior rectus: depression of the eye  All of the above originate from the ring around the optic nerve  ** if innervation not specifies, innervated by the oculomotor nerve  Superior oblique: o Rotational movement o Small pulley that runs through allows a complete change in direction o Contraction medial rotation o Innervated by the trochlear nerve CN IV  Inferior oblique: o Angles of pull o Originates from wall of the eye orbit o Lateral rotation o Inserts side of the eye  All eye muscle exit through the superior orbital fissure Muscles of the throat  Superior pharyngea constrictor  Stylopharyngeas: o Innervated by the glossopharyngeal nerve o Originates off the styloid process  Palatopharyngeus: o Involved in swallowing o Originates at the palate  Middle pharyngea constrictor  Inferior pharyngea constrictor Anterior Neck Muscles  Suprahyoid o Mylohyoid: hyoid to the inner mandible expands inner chin o Geniohyoid: hyoid to inner mandible o Digastric:  2 bellies; anterior and posterior  Attaches inner chin, through hyoid, through stirrup onto the mastoid process  Sternocleidomastoid o Originates off the sternum, attaches to the clavicle o Has two heads, inserting on the mastoid process o Contraction causes opposite movement of the head (contract the left, move the right) o Innervation is cranial nerve 9 accessory nerve  Runs through the jugular foramen  Infrahyoid o Omohyoid o Thryohyoid o Sternothyroid o Sternohyoid o These muscles depress the hyoid bone and larynx during swallowing, and speaking, they have an assortment of innervations  Scalenes o Posterior on rib two o Flex the neck o Attach to the vertebrae and ribs o Assist in breathing  Splenius Capitis o Originates from the spinous process, reaches the head o Inserts on the mastoid process  Splenius Cervicus o Does not reach the head, reaches the cervical region o Inserts on the transverse processes Back muscles  Erector Spinae; consists of the: o Iliocostalis  Runs the illium to the ribs  Inserting on the body of the rib o Longissimus  Attaches the length of the vertebral column on transverse processes  Most lateral, originates off transverse processes in the lumbar region o Spinalis  Attaches to all the spinous processes and originates @ fascia in lumbar region o Extend the trunk, maintain posture  Transversospinalis muscles o Assist in extension, lateral flexion and rotation of the vertebrae  Intertransversarius o In between the transverse process  Rotatores o Between the spinous and transverse processes  Multifidus o Spinous transverse, but skips vertebrae  Interspinalis o Spinous process to spinous process Abdominal Muscles  Serratus anterior  Pectoralis major  Linea Albae o Tendon, runs the xiphoid process to the pubic symphysis  Transverse abdominal muscle o Runs behind the rectus abdominus  Internal oblique o Attaches to the linea albae  External oblique o Inserts at the iliac crest  Rectus abdominus o Costal cartilage pubic tubercle  Internal Intercostals o Expiration o Originate the superior border o Insertion inferior border of the rib above it  External Intercostals o Originate: inferior rib o Insertion: superior border of rib below Diaphragm  Attachments: xiphoid, ribs and costal cartilages, lumbar vertebral bodies  Holes within allow other structures to pass through like the esophagus and the vena cave Muscles of the pectoral Girdle  Separated into two groups o 1. Muscles that move the shoulder girdle  a. Posterior  b. Anterior o These muscles directl1y move the clavicle or the scapula o 2. Muscles that move the humerus  Axial: anterior and posterior  Skip over the shoulder girdle  Scapular: anterior and posterior  Originate from the scapula Muscles that move the scapula POSTERIOR  Trapezius o Moves the scapula o Has three fibers groups o Innervated by the accessory nerve o Very large o Origin: the ligamentum nuche o Inserts on the spine of the scapula  Rhomboids o There is a major and minor o Runs ligamentum nuche under the trapezius o Inserts the medial scapula o Innervated by the dorsal scapular nerve o Elevates, adducts and downward rotates scapula  Levator scapulae o Innervated by the dorsal scapular nerve o Elevated and downward rotates ANTEOIR  Pectoralis minor o Inserts on the coracoid process of the scapula o Originates rib 3-5 o When contracts causes abduction of the scapula and also pulls the scapula down o Innervated by the pectoral nerve  Subclavius o Pulls the clavicle down o Innervated by the subclavian nerve  Coracobrachialis o Coracoid process to brachium of humerus  Serratus anterior o Innervated by the long thoracic nerve o Originates the length of the ribs o Inserts on the medial border of the anterior scapula o Contraction causes abduction and upward rotation o Keeps the scapula tight Muscles that move the humerus  Pectoralis Major o Innervated by the pectoral nerve o Origin: costal cartilage, sternum, clavicle o Inserts on the greater tubercle o Causes flexion of shoulder, adduction and medial rotation  Latissimus Dorsi o Thoracodorsal nerve (innervation) o Originates thoraco-lumbar fascia o Inserts on the bicipital groove (going underneath he armpit) o Causes extension adduction and medial rotation of the shoulder  Deltoids o Anterior fibers originate on the lateral third of the clavicle o The middle fibers originate on the acromion process o The posterior fibers originate on the spine of the scapula o Insertion is on the deltoid tuberosity o Innervated by the axillary nerve Rotator cuff muscles  Four muscles that reinforce the glenohumeral joint o Supraspinatus  Originates of the supraspinous fossa  Inserts on the greater tubercle  Abducts humerus o Infraspinatus  Originates of the infraspinous fossa o Teres minor  Originates of the lateral border  Inserts the lesser tubercle  Cause adduction  Cause medial rotation  Innervated by the axillary nerve o Subscapularis  Originates off the subscapular fossa Muscles of the Arm  Anterior brachium o Supinates forearm o Both heads of the muscle are closed in by tendons o Inserts on the radial tuberosity and bicipital aponeurosis  Bicep’s brachi o Cause shoulder flexion o Long head:  Originates the supraglenoid tubercle and runs within the bicipital groove  These come together to form a central belly o Both heads insert of the bicipital tuberosity o Short head  Attaches to the coracoid process  Anything lying on the anterior arm is innervated buy the musculotaneous nerve  Deeper in the arm o Brachialis  Most powerful flexor of the elbow  Inserts on ulnar tuberosity  Originates off the shaft of the humerus and attaches on the ulna  Doesn’t matter if in pronation or supination when contracts  Innervated by the musculocutaneous nerve  Posterior brachium o Three heads (a long, medial and lateral head) o Insertion- the olecranon process o The long head: allows for shoulder extension, originates on the infraglenoid tubercle o Medial and lateral head: originates on the humerus, they don’t cause extension of the shoulder, inserts on the olecranon process, and innervated by the radial nerve  Forearm (antebrachium) o Posterior: causes extension o Anterior: fl
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